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Geometry

Area, volume, and angle calculators — triangles, circles, spheres, cones, and more.

10 tools

Distance & Midpoint

Distance and midpoint between two points.

Pythagorean Theorem

Solve a² + b² = c² for any missing side.

Area & Volume

Area and volume of common 2D and 3D shapes.

Triangle Solver

Solve a triangle from sides and angles (SSS, SAS, ASA, AAS).

Circle Calculator

Radius, diameter, circumference, and area of a circle.

Sphere Calculator

Volume and surface area of a sphere from its radius.

Cylinder Calculator

Volume and surface area of a cylinder from radius and height.

Cone Calculator

Volume, slant height, and surface area of a cone.

Rectangular Prism Calculator

Volume, surface area, and diagonal of a box from its sides.

Regular Polygon Calculator

Area, perimeter, and interior angle of a regular polygon.

About geometry tools

The measurements of shapes — area, perimeter, surface area, volume, and angles for triangles, circles, and 3D solids like spheres, cylinders, and cones. Each tool shows the formula and works the numbers out step by step.

When to use these tools

Common geometry tasks and the tool that handles each one.

Frequently asked questions

Common questions about geometry — the concepts behind the tools above.

What is the difference between area and perimeter?
Perimeter is the total distance around the outside of a 2D shape and is measured in linear units such as cm. Area is the amount of surface the shape covers and is measured in square units such as cm².
How do area, surface area, and volume differ?
Area applies to flat 2D shapes and uses square units. Surface area is the total area of all the outer faces of a 3D solid, also in square units, while volume measures the space a 3D solid holds and uses cubic units such as cm³.
What is the Pythagorean theorem?
For a right triangle, the Pythagorean theorem states a² + b² = c², where a and b are the two shorter legs and c is the hypotenuse (the side opposite the right angle). It only holds for right triangles and lets you find any one side when the other two are known.
What is π (pi) and why does it appear in circle formulas?
Pi is the constant ratio of a circle’s circumference to its diameter, approximately 3.14159, and it is the same for every circle. Because that ratio is fixed, π shows up in circle measurements such as circumference C = 2πr and area A = πr².

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